1. An electronic calculator comprising: memory means including a first area for storing a program of one or more lines of one or more alphanumeric statements per line and a second area for storing a single line of one or more alphanumeric statements; keyboard input means for entering one or more lines of one or more alphanumeric statements per line into the memory means; processing means coupled to said memory means and keyboard input means for executing lines of one or more alphanumeric statements per line; and output display means coupled to said processing means for visually displaying alphanumeric information, including the results of execution of lines of alphanumeric statements, to the user; said keyboard input means including a run control key for initiating execution by said processing means of a program of one or more lines of alphanumeric statements stored in said first area of said memory means; and an execute control key for initiating execution by said processing means of a single line of one or more alphanumeric statements entered from said keyboard input means and stored in said second area of said memory means; said processing means including logic means operative for enabling entry of a line of one or more alphanumeric statements from said keyboard input means during execution of a program stored in said first area of said memory means, said logic means further including means responsive to subsequent actuation of said execute control key, during execution of said program, for temporarily halting execution of said program, for initiating execution by said processing means of said entered line of one or more alphanumeric statements and for causing the results to be visually displayed on said output display means, said logic means further including means responsive to an indication by said processing means that execution of said entered line has been completed for causing said processing means to resume execution of said program.