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Recursion in C
Function repeatedly calling itself is called recursion. But we need to specify some condition to stop execution of recursive function otherwise function may run infinite.
| Program using recursion to find factorial of a number . |
| #include<stdio.h> int fact(int no) { if(n0==1||n0==0) return(1); else return(no*fact(no-1)); } int main() { int f1,n; printf(“\nEnter a number”); scanf(“%d”,&n); f1=fact(n); printf(“\nFactorial of %d=%d”,n,f1); return(0); } |
| Output |
| Enter a number=4 Factorial of 4 =24 |
| Description |
| Function fact() check whether value of parameter no is equal to 1 or 0. In case of 1 or 0, factorial will be returned as 1 otherwise statement no*fact(no-1) will execute.
Suppose value of n is 4, execution will be as follows: f = 4* fact (3); will be evaluated. This statement again calls fact() function with value n-1 which will return value 4*fact(4-1); This process continues until value of no is equal to 1 or 0 and when no is equal to 1 it returns 1 and execution of this function stops. Process is as f0llows f1 = 4* fact (3-1); f1 =4*3* fact (3-1); f4 = 4*3*2*fact (2-1); f 1= 4*3*2*1; f = 24; |
Nesting of functions in C
It is the process in which a function calls another function.
| Program for nesting of function. |
| #include<stdio.h> void message() { printf(”\nHello”); } void disp() { printf(”Welcome”); message(); /*Function msg() nested within function show().*/ } int main() { disp(); return(0); } |
| Output |
| Welcome Hello |
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