📘 Lesson · Lesson 53

50 C Practice Programs

About

A collection of 50 important C practice programs every beginner should try — covering calculations, decisions, loops, patterns and arrays. Each program is short, complete and shows the expected output.

Basic Calculation Programs

1. Add two numbers

#include <stdio.h>
int main(){
    int a=5, b=3;
    printf("Sum = %d", a+b);  // 8
    return 0;
}

2. Subtract two numbers

#include <stdio.h>
int main(){
    int a=10, b=4;
    printf("Diff = %d", a-b);  // 6
    return 0;
}

3. Multiply two numbers

#include <stdio.h>
int main(){
    int a=6, b=7;
    printf("Product = %d", a*b);  // 42
    return 0;
}

4. Divide two numbers

#include <stdio.h>
int main(){
    float a=10, b=4;
    printf("Result = %.2f", a/b);  // 2.50
    return 0;
}

5. Find remainder (modulus)

#include <stdio.h>
int main(){
    int a=17, b=5;
    printf("Remainder = %d", a%b);  // 2
    return 0;
}

6. Area of rectangle

#include <stdio.h>
int main(){
    int l=8, w=3;
    printf("Area = %d", l*w);  // 24
    return 0;
}

7. Area of circle

#include <stdio.h>
int main(){
    float r=7;
    printf("Area = %.2f", 3.14*r*r);  // 153.86
    return 0;
}

8. Simple interest

#include <stdio.h>
int main(){
    float p=1000, r=5, t=2;
    printf("SI = %.2f", (p*r*t)/100);  // 100.00
    return 0;
}

9. Average of three numbers

#include <stdio.h>
int main(){
    int a=10, b=20, c=30;
    printf("Avg = %.2f", (a+b+c)/3.0);  // 20.00
    return 0;
}

10. Swap two numbers

#include <stdio.h>
int main(){
    int a=5, b=9, t;
    t=a; a=b; b=t;
    printf("a=%d b=%d", a, b);  // a=9 b=5
    return 0;
}

If-Else and If-Else-If Programs

1. Check even or odd

#include <stdio.h>
int main(){
    int n=7;
    if(n%2==0) printf("Even");
    else printf("Odd");  // Odd
    return 0;
}

2. Largest of two numbers

#include <stdio.h>
int main(){
    int a=12, b=20;
    if(a>b) printf("%d", a);
    else printf("%d", b);  // 20
    return 0;
}

3. Largest of three numbers

#include <stdio.h>
int main(){
    int a=5,b=9,c=3;
    if(a>=b && a>=c) printf("%d",a);
    else if(b>=c) printf("%d",b);
    else printf("%d",c);  // 9
    return 0;
}

4. Positive, negative or zero

#include <stdio.h>
int main(){
    int n=-4;
    if(n>0) printf("Positive");
    else if(n<0) printf("Negative");
    else printf("Zero");  // Negative
    return 0;
}

5. Check pass or fail

#include <stdio.h>
int main(){
    int marks=45;
    if(marks>=33) printf("Pass");
    else printf("Fail");  // Pass
    return 0;
}

6. Grade using if-else-if

#include <stdio.h>
int main(){
    int m=82;
    if(m>=90) printf("A+");
    else if(m>=75) printf("A");
    else if(m>=33) printf("Pass");
    else printf("Fail");  // A
    return 0;
}

7. Check leap year

#include <stdio.h>
int main(){
    int y=2024;
    if((y%4==0 && y%100!=0)||y%400==0) printf("Leap");
    else printf("Not Leap");  // Leap
    return 0;
}

8. Check vowel or consonant

#include <stdio.h>
int main(){
    char ch='e';
    if(ch=='a'||ch=='e'||ch=='i'||ch=='o'||ch=='u') printf("Vowel");
    else printf("Consonant");  // Vowel
    return 0;
}

9. Check divisible by 5 and 11

#include <stdio.h>
int main(){
    int n=55;
    if(n%5==0 && n%11==0) printf("Yes");
    else printf("No");  // Yes
    return 0;
}

10. Largest using ternary

#include <stdio.h>
int main(){
    int a=7, b=4;
    printf("%d", (a>b)?a:b);  // 7
    return 0;
}

Loop Programs

1. Print 1 to 10

#include <stdio.h>
int main(){
    for(int i=1;i<=10;i++)
      printf("%d ", i);  // 1 2 3 4 5 6 7 8 9 10
    return 0;
}

2. Sum of first N numbers

#include <stdio.h>
int main(){
    int n=5, sum=0;
    for(int i=1;i<=n;i++) sum+=i;
    printf("Sum = %d", sum);  // 15
    return 0;
}

3. Factorial of a number

#include <stdio.h>
int main(){
    int n=5, f=1;
    for(int i=1;i<=n;i++) f*=i;
    printf("Factorial = %d", f);  // 120
    return 0;
}

4. Multiplication table

#include <stdio.h>
int main(){
    int n=5;
    for(int i=1;i<=10;i++)
      printf("%d x %d = %d\n", n, i, n*i);
    return 0;
}

5. Print even numbers 1-20

#include <stdio.h>
int main(){
    for(int i=2;i<=20;i+=2)
      printf("%d ", i);  // 2 4 6 ... 20
    return 0;
}

6. Reverse a number

#include <stdio.h>
int main(){
    int n=1234, rev=0;
    while(n>0){ rev=rev*10+n%10; n/=10; }
    printf("%d", rev);  // 4321
    return 0;
}

7. Sum of digits

#include <stdio.h>
int main(){
    int n=123, s=0;
    while(n>0){ s+=n%10; n/=10; }
    printf("Sum = %d", s);  // 6
    return 0;
}

8. Count digits

#include <stdio.h>
int main(){
    int n=98765, c=0;
    while(n>0){ c++; n/=10; }
    printf("Digits = %d", c);  // 5
    return 0;
}

9. Check prime number

#include <stdio.h>
int main(){
    int n=13, p=1;
    for(int i=2;i<n;i++) if(n%i==0) p=0;
    printf(p?"Prime":"Not Prime");  // Prime
    return 0;
}

10. Fibonacci series

#include <stdio.h>
int main(){
    int a=0,b=1,c;
    for(int i=0;i<7;i++){ printf("%d ",a); c=a+b; a=b; b=c; }
    // 0 1 1 2 3 5 8
    return 0;
}

Pattern Programs

1. Square of stars

#include <stdio.h>
int main(){
    for(int i=1;i<=4;i++){
      for(int j=1;j<=4;j++) printf("* ");
      printf("\n");
    }
    return 0;
}

2. Right triangle of stars

#include <stdio.h>
int main(){
    for(int i=1;i<=5;i++){
      for(int j=1;j<=i;j++) printf("* ");
      printf("\n");
    }
    return 0;
}

3. Inverted triangle

#include <stdio.h>
int main(){
    for(int i=5;i>=1;i--){
      for(int j=1;j<=i;j++) printf("* ");
      printf("\n");
    }
    return 0;
}

4. Number triangle

#include <stdio.h>
int main(){
    for(int i=1;i<=5;i++){
      for(int j=1;j<=i;j++) printf("%d ", j);
      printf("\n");
    }
    return 0;
}

5. Repeated number triangle

#include <stdio.h>
int main(){
    for(int i=1;i<=5;i++){
      for(int j=1;j<=i;j++) printf("%d ", i);
      printf("\n");
    }
    return 0;
}

6. Right-aligned triangle

#include <stdio.h>
int main(){
    for(int i=1;i<=4;i++){
      for(int j=i;j<4;j++) printf("  ");
      for(int k=1;k<=i;k++) printf("* ");
      printf("\n");
    }
    return 0;
}

7. Pyramid of stars

#include <stdio.h>
int main(){
    int n=4;
    for(int i=1;i<=n;i++){
      for(int j=i;j<n;j++) printf(" ");
      for(int k=1;k<=2*i-1;k++) printf("*");
      printf("\n");
    }
    return 0;
}

8. Alphabet triangle

#include <stdio.h>
int main(){
    for(int i=1;i<=5;i++){
      for(char c='A';c<'A'+i;c++) printf("%c ", c);
      printf("\n");
    }
    return 0;
}

9. Diamond pattern

#include <stdio.h>
int main(){
    int n=3;
    for(int i=1;i<=n;i++){ for(int j=i;j<n;j++)printf(" "); for(int k=1;k<=2*i-1;k++)printf("*"); printf("\n"); }
    for(int i=n-1;i>=1;i--){ for(int j=n;j>i;j--)printf(" "); for(int k=1;k<=2*i-1;k++)printf("*"); printf("\n"); }
    return 0;
}

10. Hollow square

#include <stdio.h>
int main(){
    int n=4;
    for(int i=1;i<=n;i++){
      for(int j=1;j<=n;j++){
        if(i==1||i==n||j==1||j==n) printf("* ");
        else printf("  ");
      }
      printf("\n");
    }
    return 0;
}

Array Programs

1. Sum of array elements

#include <stdio.h>
int main(){
    int a[]={10,20,30,40}, sum=0;
    for(int i=0;i<4;i++) sum+=a[i];
    printf("Sum = %d", sum);  // 100
    return 0;
}

2. Largest in array

#include <stdio.h>
int main(){
    int a[]={3,7,2,9,4}, max=a[0];
    for(int i=1;i<5;i++) if(a[i]>max) max=a[i];
    printf("Max = %d", max);  // 9
    return 0;
}

3. Smallest in array

#include <stdio.h>
int main(){
    int a[]={3,7,2,9,4}, min=a[0];
    for(int i=1;i<5;i++) if(a[i]<min) min=a[i];
    printf("Min = %d", min);  // 2
    return 0;
}

4. Average of array

#include <stdio.h>
int main(){
    int a[]={10,20,30}, s=0;
    for(int i=0;i<3;i++) s+=a[i];
    printf("Avg = %.2f", s/3.0);  // 20.00
    return 0;
}

5. Reverse an array

#include <stdio.h>
int main(){
    int a[]={1,2,3,4,5};
    for(int i=4;i>=0;i--) printf("%d ", a[i]);  // 5 4 3 2 1
    return 0;
}

6. Count even numbers

#include <stdio.h>
int main(){
    int a[]={1,2,3,4,5,6}, c=0;
    for(int i=0;i<6;i++) if(a[i]%2==0) c++;
    printf("Even count = %d", c);  // 3
    return 0;
}

7. Search element (linear)

#include <stdio.h>
int main(){
    int a[]={5,8,12,3}, key=12, pos=-1;
    for(int i=0;i<4;i++) if(a[i]==key) pos=i;
    printf("Found at %d", pos);  // 2
    return 0;
}

8. Copy array to another

#include <stdio.h>
int main(){
    int a[]={1,2,3}, b[3];
    for(int i=0;i<3;i++) b[i]=a[i];
    printf("%d %d %d", b[0],b[1],b[2]);  // 1 2 3
    return 0;
}

9. Sort array (ascending)

#include <stdio.h>
int main(){
    int a[]={5,2,8,1}, n=4;
    for(int i=0;i<n;i++)for(int j=0;j<n-i-1;j++)
      if(a[j]>a[j+1]){int t=a[j];a[j]=a[j+1];a[j+1]=t;}
    for(int i=0;i<n;i++) printf("%d ",a[i]);  // 1 2 5 8
    return 0;
}

10. Count positive and negative

#include <stdio.h>
int main(){
    int a[]={-1,2,-3,4,5}, p=0,n=0;
    for(int i=0;i<5;i++){ if(a[i]>=0)p++; else n++; }
    printf("Pos=%d Neg=%d", p, n);  // Pos=3 Neg=2
    return 0;
}

परिचय

हर beginner के लिए 50 ज़रूरी C practice programs — calculations, decisions, loops, patterns और arrays। हर program छोटा, पूरा है और expected output दिखाता है।

Basic Calculation Programs (गणना)