Untitled

#include<stdio.h>
#include<math.h>
#include<conio.h>
int main(){
	puts("Option:");
	puts("1.sum(2,4,6,8, ...,2n )");
	puts("2.sum(3,5,7,9, ..., 2n+1 )");
	puts("3.sum(cos(1),cos(2),cos(3),...,cos(n))");
	int p;
	char op,sum;
	printf("Choose One :\n");scanf("%d",&sum);
	switch(p){
		case 1:{
		printf("Input number :");scanf("%c",&op);
		sum=
			break;
		}
		case'op2':{	("2");
		printf("%d");
			break;
		}
		case 'op3':{("3");
		printf("%d");
			
			break;
		}
	}
	return 0;
}