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# Write a C Program to swap numbers using third variable

Write a C program to swap values of two variable using third variable with algorithm and flowchart

### Alogrithm:

1. Start
2. Define a=20,b=30,temp
3. Display a,b before swap
4. temp = b
5. b = a
6. a = temp
7. Display a,b after swap
8. Stop

### Flowchart:

The a = b in the rectangle is actually a = temp{alertInfo}

### Code:

#include<stdio.h>
int main(){
int a=20,b=30,temp;
printf(“a=%d and b= %d before swapping.”, a,b);
temp = b;
b = a;
a = temp;
printf(“a= %d and b=%d after swapping.”, a,b);
}{codeBox}

### Explanation:

The value of a is 20 and b is 30 at first. A temporary variable temp is assigned. The value of temp is passed to temp and a is passed to b and again the value of temp is passed to a. In this way, the values get swapped.

Before:
a = 20;
b = 30;

temp = b;  //temp becomes 30
b = a; //b becomes 20
a = temp; //a becomes 30

After:
a = 30;
b = 20;

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