How can we find the output of recursion program in quicker way in c?

How can we find the output of recursion program in quicker way in c programming language

(1)What will be output of following c recursion program?

#include<stdio.h>
int main(){

    int x,num=4;

    x=call(num);

    printf("%d",x);

    return 0;

}

int call(int num){

    static int x=1,y;

    if(num>0){

         x=x*num;

         y=call(num-1)+call(num-2);

    }

    return x;

}

output: 48

(2)What will be output of following c recursion program?

#include<stdio.h>
int main(){

    int x,num=5;

    x=call(num);

    printf("%d",x);

    return 0;

}

int call(int num){

    static int x=1,y;

    if(num>0){

         x=x+num;

         y=call(num-2)+call(num-3);

    }

    return x;

}

Output: 12

(3)What will be output of following c recursion program?


#include<stdio.h>

int main(){

    int x,num=5;

    x=call(num);

    printf("%d",x);

    return 0;

}

int call(int num){

    static int x=1,y;

    if(num>0){

         x=x+num-1;

         y=call(num-1)+2;

    }

    return x;

}

Output: 11

(4)What will be output of following c recursion program?


#include<stdio.h>

int main(){

    int x,num=1;

    x=call(num);

    printf("%d",x);

    return 0;

}

int call(int num){

    static int x=1,y;

    if(num<4){

         x=x+num*2;

         y=call(num+1)+call(num+2)+call(num+3);

    }

    return x;

}

Output: 19

(5)What will be output of following c recursion program?


#include<stdio.h>

int main(){

    int x,num=1;

    x=call(num);

    printf("%d",x);

    return 0;

}

int call(int num){

    static int x=0,y;

    if(num<4){

         x=3*x+num;

         y=call(num+1)+2+call(num+3);

    }

    return x;

}

Output: 18

(6)What will be output of following c recursion program?


#include<stdio.h>

int main(){

    int x,num=1;

    x=call(num);

    printf("%d",x);

    return 0;

}

int call(int num){

    static int x=0;

    if(num<4){

         x=2*x-num;

         call(num+1);

         call(num+2);

    }

    return x;

}

Output: -25